Department of Pediatrics, Medical University of South Carolina, Charleston, SC 29425, USA.

Abstract

OBJECTIVE:

To examine the effectiveness of oral vitamin D(3) (400 IU) supplementation on the nutritional vitamin D status of breastfeeding infants.

DESIGN:

As part of a larger ongoing vitamin D RCT trial of lactating women, infants of mothers assigned to control received 1 drop of 400 IU vitamin D(3)/day starting at one month of age. Infant 25(OH)D levels (mean +/- S.D.) were measured by RIA at visits 1, 4, and 7.

As shown in and , analyzing all values per study visits 1, 4, and 7, there was a significant rise in 25(OH)D levels in those infants randomized to the 400 IU vitamin D3/one drop/day regimen. Of the 33 infants who have completed the study, the mean levels increased from 16.0 ± 9.3 ng/mL (baseline; range 1.0–40.8 ng/mL; median 13.4) to 43.6 ± 14.1 ng/mL (range 18.2–69.7) at 4 months and remained relatively unchanged at month 7 : 42.5 ± 12.1 ng/mL (range 18.9–67.2). As defined by circulating 25(OH)D levels <20 ng/mL, of the 33 infants, 24 (72.7%) had evidence of deficiency at one month of age. The change in values between 1 and 4 months and 1 and 7 months was statistically significant (P ≤ .0001). As predicted, there were no statistically significant differences between months 4 and 7 (P = .66). Repeated measures ANOVA indicated overall significance (P < .0001). The difference was unaffected by seasonal variation (). There was no toxicity observed in the infants based on serum calcium, phosphorus, and creatinine levels. In addition, there were no adverse health effects attributed to vitamin D supplementation.